The UCLA-University of Utah epidemiologic survey of autism: recurrence risk estimates and genetic counseling

Abstract

The authors recently reported, in this journal, an epidemiologic survey of autism in Utah. Twenty (9.7%) of the 207 families ascertained had more than one autistic child. Analyses of these data revealed that autism is 215 times more frequent among the siblings of autistic patients than in the general population. The overall recurrence risk estimate (the chance that each sibling born after an autistic child will develop autism) is 8.6%. If the first autistic child is a male the recurrence risk estimate is 7%, and if a female 14.5%. These new recurrence risk estimates should be made available to all individuals who have autistic children and are interested in family planning.

The Familial Risk of Autism

“…Only few earlier studies have had the possibility to calculate the RR 8,27,28 . Two studies are presenting self-selected samples 8,28 and with limited family data.…”

“…Two studies are presenting self-selected samples 8,28 and with limited family data. A recent Danish study provide reliable estimates using an excellent epidemiological sample similar to ours.…”

“…Our bigger sample also allowed us to investigate sex of offspring in some more detail. Several earlier studies have reported absolute sibling recurrence risk 28–34 but absolute risk is a cumulative measure which depends on the length of follow up (higher at age 15 years than at age 5 year) and will differ between populations. As elsewhere in epidemiology, where the relative risk is a preferred measure of disease risk, the RR circumvent these limitations.…”

Perinatal Exposure to Traffic-Related Air Pollution and Autism Spectrum Disorders

“…Early twin and family studies suggested ASD to be highly heritable (Bailey et al 1995; Lichtenstein et al 2010; Ritvo et al 1989); however, recent studies have shown a moderate heritability for ASD (Ronald et al 2011; Sandin et al 2014), suggesting a substantial nongenetic component contributing to the etiology of the disorder. Moreover, twin studies have recently reported a modest genetic component but a significant environmental contribution to the correlation between ASD and ID (Hoekstra et al 2009, 2010).…”

The International Collaboration for Autism Registry Epidemiology (iCARE): Multinational Registry-Based Investigations of Autism Risk Factors and Trends

“…Autism was differentiated as a specific set of child disorders in the 1940s, and early work considered mother–child interactions as potential causes (Bettelheim 1972). By the 1980s, however, studies had established that there was a strong genetic contribution to ASD (Folstein and Rutter 1977; Steffenburg et al 1989; Ritvo et al 1989). Since then, etiological research in ASD has focused primarily on genetic factors.…”